Folding knives, or so-called pocket knives, have been around for over a hundred years and are well known in the art. Initially, folding knives were a single blade housed between two handle portions and rotatable around a pivot point such as a screw or rivet at one end of the handle. During use, the blade is rotated approximately 180 degrees such that the blade extends from the handle and the blade and handle share a common longitudinal plane. The handle and tang end of the blade come in contact to prevent the blade from over-rotating and to provide a solid cutting implement. For storage, the blade is rotated the opposite direction the same approximate 180 degrees, and stored in a cavity within the handle. With the blade stored, the overall length of the knife is approximately 40% shorter, thereby allowing for convenient storage in, for example, a pocket. The small size of such a knife makes it desirable as a portable and efficient means of having a cutting implement available at all times.
Over time, many improvements have been made to the basic pocket knife premise to improve both function and aesthetics. For example, one or more additional blades have been added to provide options for blade shape, size, and utility. Additionally, other implements and tools have been added, up to and including eating utensils, flashlights, cork screws, screwdrivers, lanyards, scissors, and a seemingly endless myriad of other useful tools. As one might expect however, the addition of tools adds to the overall size of the folding knife, thereby decreasing the ease of storage, and potentially the desirability of carrying the knife in the first place. The result is a give-and-take analysis where one must prioritize the function and use frequency of each potential tool, and then weigh that against the physical size of the tool and how it will be carried by the user. This general development has also led to other useful items incorporating a folding knife blade into them. For example, carabiners, flashlights, key chains, etc. have been modified to have a blade contained somewhere within their respective frames.
Another general area of improvement has been in the opening of the knife blade. Originally, the blade had a recess cut into the side of the blade where a fingernail could catch and extract the blade from its stored position. The need and/or desire for the ability to open a blade using only one hand spurred a number of competing modifications, such as a thumb stud mounted on the side of the blade, a portion of the blade tang protruding out of the handle, or even a button released spring-assisted opening mechanism. Some of these mechanisms that exert stored potential energy on the blade and eject the blade from the storage cavity at high speed have been classified as illegal weapons and subsequently outlawed in some, but not all, jurisdictions. This causes considerable problems for a person who may legally carry such a knife in his own jurisdiction, and therefore without thinking carries it into another jurisdiction where it has been outlawed. One common feature though, is the placement of a release button or operating lever for a blade-opening device. Traditional placement of such mechanisms has been on the side of the blade or on the side of the handle, enlarging the tool and potentially providing a point where clothing or other items can be snagged or caught on the mechanism.
Although there are many options in the folding knife technology area, there is an ongoing desire to improve space efficiency and use of such knives. What is desired then, is an improved knife that maximizes space utilization, and that provides a mechanism for easily opening a blade with one hand while minimizing the size of the mechanism and optimizing its location.